Data strobe encoding and recovered clock.

Data strobe encoding (or D/S encoding) is an encoding scheme for transmitting data in digital circuits. It uses two signal lines (e.g. wires in a cable or traces on a printed circuit board), Data and Strobe. These have the property that either Data or Strobe changes its logical value in one clock cycle, but never both. This allows for easy clock recovery with a good jitter tolerance by XORing the two signal line values.

Data strobe encoding is used on the signal lines in the IEEE 1394 (aka FireWire 400) system.